tyre pressure

spencer_uk

Hi - bit of a noob questions this - but I need some help. I am riding with some slime tubes on. My tyre says it takes 100psi however the tube doesn't say anything (other than in the instructions it says inflate to the correct pressure). When I blew them up to 100 it seemed as if they'd pop (given they got rigid around the 60psi point). So Iet them down to the point where they now have a little give (around 50psi). What is the correct pressure? Should I make them take to the point that the tyres say? Or to the point where they become bone rigid? Or should they have a little give? Last thing I want is a blow-out because I over-inflated. My tyres are Maxxis Columbiere's that came on my Giant Escape R2.

Thankis

Big Red S

The tube does (almost) nothing structural. The tyre and rim resist the pressures, and the tube's only there to be airtight.

The 'right' pressure is within the minumum and maximum pressures on the sidewall of the tyre, and below the maximum for the rim.

For a reasonable quality rim and a narrow tyre, 80-100psi is the right kind of ballpark. Thinner tyres want higher pressures, generally. And the thinnest don't want to give at all.

DavidTQ

I tend to run my tyres at the maximum recommended pressure, a "little" give on a thumb test can be more than enough to cause a pinch flat when riding over a bump. Higher pressures make more efficient use of your pedalling energy. My road bike tyres are at 120ish PSI and feel rock solid if the pressure drops below 90 psi I can really feel the extra drag.

el_presidente

My front tyre is 700x20c and rated to 160 psi ! I lost my nerve when it got 140 psi on the track pump guage

spencer_uk

thanks guys - I'll pump to 100 psi then and hope not to hear a bang.

As an aside - I have no idea how I'd be able to get to 100 psi on the road with a mini-hand pump though if it blows there. That'll be more exhausting than the ride itself!

el_presidente

spencer_uk wrote:

thanks guys - I'll pump to 100 psi then and hope not to hear a bang.

As an aside - I have no idea how I'd be able to get to 100 psi on the road with a mini-hand pump though if it blows there. That'll be more exhausting than the ride itself!

You'll struggle, just get it has hard as you can then top it up with the track pump when at home. Or get a CO2 inflator

Bassjunkieuk

spencer_uk wrote:

thanks guys - I'll pump to 100 psi then and hope not to hear a bang.

As an aside - I have no idea how I'd be able to get to 100 psi on the road with a mini-hand pump though if it blows there. That'll be more exhausting than the ride itself!

I've got a Master Blaster Pocket Rocket hand pump, and despite the guy at the LBS saying I'd never get to the correct pressure for my tyres, I did in fact manage to get them upto 100PSI using the little hand pump, so it is indeed possible :-)

Most of the other replies are correct in stating you should run your tyres at the pressure on the sidewall, this will basically allow the wheels to take the load correctly and why narrow tyres need to go much higher then wide ones, as they have less surface to take the load.

marts500

Can i swap the presta tubes on my hybrid bike for schraeder valve type tubes without drilling the rim?